<template>
    <div class="card">
      <header>
        <slot name="header">默认头部内容</slot>
      </header>
      <main>
        <slot>默认主体内容</slot>
      </main>
      <footer>
        <slot name="footer">默认底部内容</slot>
      </footer>
    </div>
  </template>
  
  <style scoped>
  .card {
    border: 1px solid #ccc;
    width: 400px;
    border-radius: 5px;
    padding: 20px;
    margin-bottom: 20px;
  }
  
  main {
    height: 60px;
  }
  
  header, footer {
    height: 80px;
    padding: 10px 0;
  }
  </style>